Blind stitch sewing machine



Dec. 18, 1934. C W, MUELLER 1,984,754 4 BLIND STITCH SEWING MACHINE 3 Sheets-Sheet 1 Filed Nov. 18, 1931 3nventor, k: )7. J/ r,

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Dec. 18, 1934.

C. W. MUELLER BLIND STITCH SEWING MACHINE 3 Sheets-Sheet 2 3nventor,

' Gttorneg 1w lam/age Filed Nov. '18, 1951 C. W. MUELLER 1 BLIND STITCH SEWING MACHINE Dec. 18, 1934.

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through" the front portion ofthe foot and the Patented Dec. 18, 1934 I e 1,984,754 BLIND STITCH SEWING momma PKEENTJLLTOFFICE "Charles w.- Mueller, St. Louis, Mo., assignor to Lewis Invisible Stitch. Machine Company,

St. Louis, Mi, a corporation of Maine Application November 18, 1931, Serial No; 575,891

This: invention relates to new'and useful improvements inblind stitch sewing'machines generally, although-more particularly to machines for, blind stitching hems along the, bottoms ofskirts andonother articles of wearing apparel. Among the several objects of my invention are to provide a hemmer which is located in advancecof theridge formingielement and is capableof having its core and scroll relatively adjustedlaterally to compensate for materials of different. thicknesses, and to vary the distance between the inner edge of the hemand the point-of. needle penetration; to provide'a, vertically yielda'ble auxiliary feed dog section which is disposed directly'below the hem for cooperation with the stationary-.presser foot to accommodate hems of different thicknesses and to feed the same, and toclamp the: hem against the foot during the setting of the stitcheswhereby the hem will be retained against being" curled or rolled; and to provide a hemming mechanism of the character' described which is simple in construction and durable in operation.

With these and other objects inviewwhich will more fully appear, the nature oftheinvention will be more clearly understood b following thedescription, theappended claims and the several'views illustrated in the accompanying drawings. l 7

In the drawings:- I

Figure '1 is a horizontal'sectional view taken directly above the stationary presser' footof' a blind stitch sewing' machine embodyingmy invention and showing the fabric being'hemmed',

Figure 2 is a left hand elevation thereof, .the

stitch forming mechanismand the top feed be- I Figure 4is'a vertical sectional view taken onthe line' 4-4 of Figure 1', I

Figure-x5} is a top plan view of the 'presser foot with the scroll portion of the hemmer, re-

moved,

Figure 6" isia bottom plan'view of the presser foot: with the :complete hemmer attached there to, I r

Figure. 'I is a plan view "of the worlrjclamp, the ridge forming element, and' the feeding means, 1 I i Figure 8is a detail crosssectional view taken through the main and auxiliary feed dogs,

Figure 9 is a perspective view'of the main feed Figure 10 is a perspective View of the auxiliary feeddog, v

Figure 11 is a cross sectional view taken hemmer,

' Figure 12 is a perspective view of the scroll portion of the hemmer, r

Figure 13 is 'a plan view of a hemmed fabric. blind stitched by alineof single thread chain stitches, and I a r Figure 14 is a similar view but showingthe hem blind stitched by a line of loci; stitches. Referring to the accompanying drawings, I have s hown my invention applied to thewell known Lewis single threadchain stitchfmachine which-includes a stitching head A anda Work arm B. A stationary presser foot C is rigidly attached tothe stitching head, and disposed below the footand cooperating-therewith in the usual' manner is a vertically yieldable' Work clamp D, aA-Ihotionmain feed dog E, and a vertically; reciprocatory ridge forming element or plunger F which projects a node or ridge or posedabove the foot and supported by the stitching head is the usual blind stitch forming mechanism which may be ofany suitable type. In thepresent instance, I have, disclosed the usual single thread stitch forming mechanism which includes a curved needle 6 and ac-motion looper '7, the needle oscillating in a vertical plane which contains the plunger F. and is disposedat rightangles'to the line of feed.

The presser-foot C at the front end thereof,

is provided with a centrally located and rear-, wardly extending slot 8 forming resultant toe portions 9 and 10 respectively, the slot' 8 being disposed directly in front of the plunger openlongitudinalgroove 11 formed'in'theunder face of a bridge 12- which integrally connects said toe portions.

C' and projecting into the slot 8 thereof is a hammer H for forming'the, hemg in the fabric G. This hemmer consists of two portions, a core 13'and a surrounding scroll 14. The core 13 projects longitudinally into 'the slot 8 and terminates at its rear end in spaced relation to and in front of the groove 11, the longitudinal plane of the core being in substantial registry with the right hand Wall'5' of the opening 50f the presser foot. The core is [provided at its rear end with a laterally extending attaching arm 15 which is mounted in a horizontal opening'extending transversely in the toe 9 of thefoot and secured therein by a clamp screw 16. The scroll ing 5 and communicating therewith'through a Attached ,to'the frontend, of'the presser foot ,4 v

14 is rigidly connected to a holder 17 which is mounted on the toe 10 of the foot for lateral adjustments. To this end, the holder 17 is provided on its under face with a tongue 18 which engages in a groove 19 formed in a rectangular attaching plate 20. The plate 20 is disposed, under the toe 10 of the presser foot and is provided with two openings 21, 21 through which the shanks of clamping screws 22, 22 pass upwardly into threaded openings formed in the toe, the openings being larger in diameter than the screw shanks to permit of the plate being adjusted laterally relative to the toe. The left vertical wall 20 of the plate extends along side of but in spaced relation to the core 13 and scroll 14 of the hemmer H, and along the right side of but in spaced relation to the right hand wall 5 of the opening 5 of the foot, and therefore constitutes a vertical guide for the hem for directing the latter from the hemmer past the needle 6 and the ridge forming element F. The shank of a clamping screw 23 passes upwardly through an opening 24 formed in the front end of the plate 20 and engages in a threaded opening in the holder 17, thereby permitting the holder to be adjusted laterally relative to both the plate 20 and the presser foot C.

It will, therefore, be apparent that by laterally adjusting the plate 20, the outer folded edge of the hem g may be variably positioned relative to the line of needle penetration and therefore the distance between the line containing the points of needle penetration and the inner edge of the hem maybe varied, and that by laterally adjusting the holder 17 relative to the plate 20, the scroll 14 will be thereby laterally adjusted relative to the core 13 to compensate for the adjustment previously described. It will furthermore be observed that by laterally adjusting the holder 17 relative to the core 13, the capacity of the folder may be varied so as to permit the hemming of fabrics of different weights within certain limits.

The main 4-motion feed dog E as shown in Figure 9, includes a supporting shank 25 to which a relatively long feed surface 26 is integrally attached. This feed dog operates in a feed slot (1 formed in the work clamp D which is disposed at the left of the ridge forming element or plunger F and extends from a point in front of the bridge 12 of the presser foot to a point in rear of the ridge forming element. Thus the main feed dog section 26 engages the body fabric G and feeds the same rearwardly from the hemmer H past the ridge forming element F. Rigidly connected to the shank 25 of the main feed dog E adjacent the rear end thereof is a laterally extending arm 27 which integrally supports a centrally located and relatively short feed section '28. This feed section 28 is disposed in rear of and in spaced relation to the ridge forming element F and cooperates with the feed section 26 to feed the body fabric rearwardly in rear of said ridge forming element. The feed section 28 is supported on the arm 2'7 through the medium of a vertical shank 29 and the right hand edge of the feed section overhangs the shank 29 as indicated at 30 in Figure 9'to form a resultant stop shoulder.

feed dog X is yieldably mounted whereby hem folds of different thicknesses due to different Weightsof materials may be automatically accommodated. The auxiliary feed dog X includes a supporting bar 31 and a relatively long and narrow feed section 32 which is integral or otherwise fixedly secured to the bar. This bar is located above the arm 27 and below the stop shoulder 30, and the rear end of the bar is pivotally connected to the shank 29 by a horizontal pivot screw 33. The rear end of the feed section 32 is cut away to form a limiting stop 34 which is adapted to engage the stop shoulder 30 and thereby limit the upward movement of the auxiliary feed dog relative to the main feed dog. A coil spring 35 has its upper end seated in a recess formed in the bar 31 and the lower end of this spring rests upon the arm 27. Thus the spring 35 which is disposed in front of the pivot screw 33 yieldably retains the stop 34 against the stop shoulder 30. The auxiliary feed section 32 is located immediately in front of the feed section 28 and. cooperates with the under face of the presser foot C between the right hand side wall 5 of the opening 5 and the left hand guide wall 20 of the plate 20. Thus the auxiliary feed section 32 yieldably clamps the outer folded portion of the hem g at the right of the line of needle penetrations and cooperates with the presser foot to clamp thehem therebetween and thereby prevent the setting of the stitches from curling or rolling the hem.

The presser foot C, in rear of the opening 5, is formed with a longitudinally extending opening 36 through which a top feed dog 3'7 projects and engages the hem g which has been stitched. This top feed dog may be of any suitable construction, although 1 preferably employ a 4-motion feed dog.

From'the foregoing, it will be observed that I have provided a blind stitch sewing machine with a hemmer attachment which is adjustable laterally not only to compensate for different Weights of materials but also to vary the line of needle penetration at the hem relative to the inner edge of said hem, and that I have provided a main bottom feed for feeding the body fabric past the stitch forming mechanism and an auxiliary body feed which is yieldably mounted on the main feed for cooperation with the hem whereby hem folds of different thicknesses, due to different weights of materials, will be automatically accommodated.

It is of course to be understood that the details of structure and arrangements of parts may be variously changed and modified without departing from the spirit and scope of my invention.

I claim:

1. In a blind stitch sewing machine, the combination with a stationary presser foot having an opening, of a feeding means cooperating with the foot to feed the material rearwardly, a stitch forming mechanism including a reciprocatory needle located above the foot and having its penetrating stroke in a plane extending across the line of feed, a ridge forming element for projecting a ridge of material upwardly through the opening of the foot and into the path of movement of the needle, the foot in front of the opening thereof being provided with a rearwardly extending slot and with a groove in the under surface of the foot in communication with the "opening and slot, and a hemmer located in the slot in front of the groove and Cir including a core and a surrounding scroll respectively supported on the foot on opposite sides of the slot.

2. In a blind stitch sewing machine, the combination with a stationary presser foot having an opening, of a feeding means cooperating with the foot to feed the material rearwardly, a stitch forming mechanism including a reciprocatory needle located above the foot and having its penetrating stroke in a plane extending across the line of feed, a ridge forming element for projecting a ridge of material upwardly through the'opening of the foot and into the path of movement of the needle, the foot in front of the opening thereof being provided with a rearwardly extending slot and with a groove in the under surface of the foot in communication with the opening and slot, a plate mounted on the foot for lateral adjustments in front of the opening thereof and on one side of said slot, and a hemmer located in the slot and including a core mounted on the foot on the side of the slot opposite the plate and a surrounding scroll mounted on said plate.

3. In a blind stitch sewing machine, the combination with a stationary presser foot having an opening, of a feeding means cooperating with the foot to feed the material rearwardly, a stitch forming mechanism including a reciprocatory needle located above the foot and having its penetrating stroke in a plane extending across the line of feed, a ridge forming element for projecting a ridge of material upwardly through the opening of the foot and into the path of movement of the needle, the foot in front of the opening thereof being provided with a rearwardly extending slot and with a groove in the under surface of the foot in communication with the opening and slot, a plate mounted on the foot for lateral adjustments in front of the opening thereof and on one side of said slot, and a hemmer located in the slot and including a core mounted on the foot on the side of the slot opposite the plate and a surrounding scroll mounted on said plate for lateral adjustments relative to the core.

4. In a blind stitch sewing machine, the combination with a stationary presser foot having an opening, of a feeding means cooperating with the foot to feed the material rearwardly, a stitch forming mechanism including a reciprocatory needle located above the foot and having its penetrating stroke in a plane extending across the line of feed, a ridge forming element for projecting a ridge of material upwardly through the opening of the foot and into the path of movement of the needle, the foot in front of the opening thereof being provided with a rearwardly extending slot and with a groove in the under surface of the foot in communication with the opening and slot, and a plate attached to the under surface of the foot at one side of the slot and including a vertical hem-guiding wall extending rearwardly along the slot, along the groove, and along the opening, and a hemmer located in the slot and mounted on the foot in front of the groove.

5. In a blind stitch sewing machine, the combination with a stationary presser foot having an opening, of a feeding means cooperating with the foot to feed the material rearwardly, a stitch forming mechanism including a reciprocatory needle located above the foot and having its penetrating stroke in a plane extending across the line of feed, a ridge forming element for projecting a ridge of material upwardly through the opening of the foot and into the path of movement of the needle, the foot in front of the opening thereof being provided with a rearwardly extending slot and with a groove in the under surface of the foot in communication with the opening and slot, and a plate attached to the under surface of the footfor lateral adjustments relative thereto and at one side of the slot and including a vertical hem-guiding wall extending rearwardly along the slot, along the groove, and along the opening, anda hemmer located in the slot and including a core mounted on the foot on the side of the slot opposite the plate and a surrounding scroll mounted on said plate.

6. In a blind stitch sewing machine, the combination with a stationary presser foot having an opening, of a stitch forming mechanism disposed above the foot and including a reciprocatory needle movable across the opening, a ridge forming element for projecting a ridge of material upwardly through said opening into needle penetrating position, a hemmer disposed in front of the opening and in fixed relation to the foot, a bottom 4-motion feed cooperating with the foot to feed the body fabric and the hem rearwardly from the hemmer past the stitch forming mechanism, the feed including a vertically yieldable feed section disposed under the hem for cooperation therewith.

7. In a blind stitch sewing machine, the combination with a stationary presser foot having an opening, of a stitch forming mechanism disposed above the foot and including a reciprocatory needle movable across the opening, a ridge forming element for projecting a ridge of material upwardly through said opening into needle penetrating position, a hemmer disposed in front of the opening and in fixed relation to the foot, a bottom 4-motion feed cooperating with the foot to feed the body fabric and the hem rearwardly from the hemmer past the stitch forming mechanism, the feed including a main feed dog and a vertically yieldable auxiliary feed dog pivotally supported by the main feed dog to move therewith and disposed under the hem for cooperation therewith.

8. In a blind stitch sewing machine, the combination with a stationary presser foot having an opening, of a stitch forming mechanism dis.

' side of the presser foot opening for engaging the body fabric and an auxiliary feed dog including a feed section extending along the other side of said opening for engaging the hem.

CHARLES W. MUELLER. 

